Type Inheritance and Relational Theory

Preface

This book will tell you more than you might have wanted to know about the subject of type inheritance (inheritance for short). Now, if you’re reading these remarks, you’re already rather special; most people don’t bother to read prefaces at all. For that reason, the kind of thing that usually goes into a preface—background material, motivation underlying the work described, reasons for writing the book, “what you will learn,” and so forth—I’ve deliberately deferred, mostly, to the body of the book (to Chapters 1 and 3 in particular). In any case, there’s really too much of that general nature that I want to say, and it’s too involved and interwoven, to fit comfortably into a conventional preface. But this is still a convenient place to take care of a few boilerplate items.

Right at the outset, I must make it clear that this is a book with an attitude. My friend and colleague, Hugh Darwen, and I have been working for many years on the theory on which this book is based: namely, our inheritance model. As a consequence, we have some very definite opinions about the subject matter, and—speaking purely for myself here—those opinions have had a major influence on the style and content of the writing. In some respects, in fact, the book isn’t so much a textbook as it is a plea for the community at large to take a careful look at what we’ve done: a careful look, in fact, at what we consider to be a logical, sensible, and pragmatically useful approach to the subject. That said, ...